How long would it take for zombies to take over the earth during a zombie apocalypse?

If you think you can survive the zombie apocalypse, you might want to think again!

A scientific study conducted at the University of Leicester and published in their Journal of Physics Special Topics predicts the outcome for a zombie outbreak is not good. Humans would not last very long at all. In fact, the prediction is that given a world population of 7.5 BILLION people, there would only be 273 humans left after 100 days! Yes, that’s right, if a zombie outbreak happened, only 100 days later, practically the whole planet would be wiped out and zombies would take over the earth!

The study, which was conducted by university students, used the SIR model which is a scientific model used to calculate the infection rate of a contagious disease. In the study, there are two basic things which are assumed about the zombies. First and foremost, it is assumed that the zombies can live 20 days without food. Second, it is assumed that there is a 90% chance that each zombie will infect one human per day. The aforementioned outcome is bleak – after a little over 3 months, there would hardly be enough people left on the planet to fill an elementary school!

Your best chance for survival during a zombie apocalpyse? Get out of the main cities. Find a remote area that’s geographically isolated from the major urban centers. From there, band together with whatever humans are left to eradicate any zombies that may already be in town or may accidentally wander through. After that, it’s a waiting game to see if the zombie population will eventually die off on it’s own – after all, once all the humans are turned into zombies, the hope is that since their is no longer a food source, the zombies could die out naturally after about 20 days. Your ultimate and final goal: wait and see if you can outlast their hunger!

1 Response

Let’s assume that a reanimating “Z-factor” – of whatever etiology, chemical or biological, could cause a “zombie”, and let’s assume that the factor is passed to humans via contact transmission vectors such as wounds, mucous membranes, etc.

Once the human organs cease functioning and the processes of death begin, the Z-factor would have to provide nutrients and oxygen to three systems at minimum in order to keep the zombie functional – brain, neural network, and musculature. Without a working cardiopulmonary system the Z-factor would have to work osmotically, either digesting organic material the zombie had “eaten”, or cannibalizing the zombie’s own dead tissues and somehow removing cellular waste products.

Without a working heart the blood would seek the lowest point in the body by gravity, usually the buttocks and back on a supine corpse and in the feet and legs of a ambulating zombie. This blood would congeal and the water content would begin to osmotically draw out into the tissues, swelling them and causing the skin to blister and crack open. The serosanguinous fluids would saturate any footwear the zombie was wearing and provide open portals for bacteriological colonization as well as other parasites and maggot breeding areas. As this continues it would break down the zombies feet, further degrading their ability to run or walk.

Regardless of how well the Z-factor could work it could not be as efficient as a working cardiopulmonary system, and the lactic and uric acids produced by the musculature during muscle work would quickly build up in the muscles and incur oxygen debt which the Z-factor could not pay except extremely slowly. This means that the muscles would stop working and freeze up rather quickly, and it would take an extremely long time, perhaps hours, for the zombie to be able to move again.

The abdominal organs would begin to decay, filling the abdomen with gases as they putrefy, and this would eventually cause the abdomen to rupture, spilling the putrefying material down the zombie’s front, allowing even more colonization by parasites and bacteria and hastening the necrotic processes of death and decay. The bladder and sphincter would relax, spilling their contents down the zombie’s legs and drawing even more insects, parasites and bacteria as well as combining with the serosanguinous fluids and putrefying organs to produce a smell that could be detected for many, many yards away.

Assuming the zombie could get ahold of a human, if it bit down its jaws could not be any stronger than they were in life, and this means that as long as a person wore reasonable clothing of a thick enough layer or layers, say denim or leather, then the zombie simply could not bite through. If it could rip away chunks of human flesh, and swallow them, then the stomach and intestines could not digest them. Digested nutrients are broken down chemically in the intestinal tract and pass through the intestinal membrane into the bloodstream where they are carried to each cell for nutrition. A zombie no longer has that blood supply, and the gall bladder would no longer be functional, so no digestion can take place, and the stomach and esophagus would eventually fill up and overflow with rotting meat. The Z-factor could colonize the stomach and break down the meat itself, carrying nutrients osmotically to the needed tissues of the brain, nervous system, and musculature.

The problem is that with all this going on, the zombie would be extremely slow, prone to long periods of no movement, unable to run or perform sophisticated actions, such as climbing, it would be noxious, emitting a miasma of decay that would draw flies and insects swarming around it, it’s feet and legs would be so swollen and cracked open that the flesh and muscles would likely slough off within days, dropping the zombie to the ground as the bones of its feet began to come apart, and without a steady source of “food” the Z-factor would continue cannibalizing the zombie’s dead tissues until the whole thing fell apart in a liquefying, putrefying puddle of rotting tissue and organs, unable to do more than twitch. A zombie would have a week at best (and less in humid, hot climates). In the winter (subfreezing temperatures) a zombie plague couldn’t happen at all. Without an efficient digestion system to provide caloric heat to keep the zombie warm, the intra and intercellular fluid surrounding the brain and inside each brain cell would freeze and expand, rupturing the brain cells from the inside out and causing traumatic and catastrophic destruction to the brain, destroying the zombie.

In reality no such thing exists, but it is possible that a weaponized form of the rabies virus could be engineered that would “turn off” the rational, logical, thinking centers of the brain and “dial up” the hunger and rage sensations, coupled with the rabid delusional state to produce a living rage “zombie” that would be infectious and raging in hours, not days.